The present invention relates to a preheating and drying device for polymeric and other materials.
Before a material, such as a polymeric material, is processed, it is important to remove contaminants and moisture from the material to prevent defects such as warping, uneven shrinkage and undesirable discoloration. Many devices have been developed in the past that remove such contaminants and moisture. However, such conventional devices are often very expensive to manufacture, unreliable and require long production cycles. There is a need for an inexpensive and reliable device for heating and drying a material to remove contaminants and moisture before it is further processed.
The preheating and drying device of the present invention has a housing and a first collector is disposed inside the housing. A feeding device extends into the housing and contains a material to be dried and preheated. A movable and hollow central conduit extends from the upper end of the housing to a bottom portion of the first collector. The central conduit carries a hot and dry air into the housing. A first and a second conical shields are attached to the central conduit. The central conduit is movable between a first open position and a second closed position. The second conical shield is tightly held against the first collector to close the bottom opening thereof when the central conduit is in the second closed position and the second conical shield is separated from the first collector when the central conduit is in the first open position to permit the material to flow through the bottom opening.